Add simple check for determining if user's offline while uploading

js/components/ascribe_uploader/react_s3_fine_uploader.js

@@ -479,8 +479,12 @@ const ReactS3FineUploader = React.createClass({
         } else {
             matchedErrorClass = testErrorAgainstAll({ type, reason, xhr });
 
-            // If none found, show the next error message
-            if (!matchedErrorClass) {
+            // If none found, check the internet connection
+            // TODO: use a better mechanism for checking network state, ie. offline.js
+            if ('onLine' in window.navigator && !window.navigator.onLine) {
+                matchedErrorClass = ErrorClasses.upload.offline;
+            } else {
+                // Otherwise, show the next error message in the queue
                 matchedErrorClass = ErrorQueueStore.getNextError('upload');
             }
         }

js/constants/error_constants.js

@@ -121,6 +121,9 @@ const ErrorClasses = {
         },
         'contactUs': {
             'prettifiedText': getLangText("We're having a really hard time with your upload. Please contact us for more help.")
+        },
+        'offline': {
+            'prettifiedText': getLangText('It looks like your Internet connection might have gone down during the upload. Please check your connection and try again.')
         }
     },
     'default': {